Deuteronomy Chapter 7, Verse 9

9: Know therefore that the LORD thy God, he is God, the faithful God, which keepeth covenant and mercy with them that love him and keep his commandments to a thousand generations;- edit KJV text
9: And thou shalt know that the Lord thy God, he is a strong and faithful God, keeping his covenant and mercy to them that love him, and to them that keep his commandments, unto a thousand generations:— edit Douay text
9: Thou shalt know therefore, that the Lord thy God, he [is] God, a faithful God, who keeps covenant and mercy for them that love him, and for those that keep his commandments to a thousand generations,— edit LXX text